1. Field of the Invention This invention relates in general to disk drives, and in particular to a gasket frame for grounding an actuator flex cable and method of using the same, wherein the actuator flex cable gasket grounds the actuator flex cable to the disk drive casting.
2. Description of Related Art
Moving magnetic storage devices, especially magnetic disk drives, are the memory devices of choice. This is due to their expanded non-volatile memory storage capability combined with a relatively low cost.
Magnetic disk drives are information storage devices which utilize at least one rotatable magnetic media disk having concentric data tracks defined for storing data, a magnetic recording head or transducer for reading data from and/or writing data to the various data tracks, a slider for supporting the transducer in proximity to the data tracks typically in a flying mode above the storage media, a suspension assembly for resiliently supporting the slider and the transducer over the data tracks, and a positioning actuator coupled to the transducer/slider/suspension combination for moving the transducer across the media to the desired data track and maintaining the transducer over the data track center line during a read or a write operation. The transducer is attached to or is formed integrally with the slider which supports the transducer above the data surface of the storage disk by a cushion of air, referred to as an air-bearing, generated by the rotating disk.
Alternatively, the transducer may operate in contact with the surface of the disk. Thus, the suspension provides desired slider loading and dimensional stability between the slider and an actuator arm which couples the transducer/slider/suspension assembly to the actuator. The actuator positions the transducer over the correct track according to the data desired on a read operation or to the correct track for placement of the data during a write operation. The actuator is controlled to position the transducer over the desired data track by shifting the combination assembly across the surface of the disk in a direction generally transverse to the data tracks. The actuator may include a single arm extending from a pivot point, or alternatively a plurality of arms arranged in a comb-like fashion extending from a pivot point. A rotary voice coil motor (vcm) is attached to the rear portion of the actuator arm or arms to power movement of the actuator over the disks.
The vcm located at the rear portion of the actuator arm is comprised of a top plate spaced above a bottom plate with a magnet or pair of magnets therebetween. The vcm further includes an electrically conductive coil disposed within the rearward extension of the actuator arm and between the top and bottom plates, while overlying the magnet in a plane parallel to the magnet. In operation, current passes through the coil and interacts with the magnetic field of the magnet so as to rotate the actuator arm around its pivot and thus positioning the transducer as desired.
The magnetic media disk or disks in the disk drive are mounted to a spindle. The spindle is attached to a spindle motor which rotates the spindle and the disks to provide read/write access to the various portions on the concentric tracks on the disks.
One or more electrical conductors extend over the suspension assembly to electrically connect the read/write transducer to a read/write chip on the actuator arm. A multiline flexible printed circuit cable (actuator flex cable) provides the electrical contact between the read/write chip and the disk drive electronics which are mounted outside the disk drive housing. Inside the disk drive housing, the actuator flex cable connects to an electrical connector pin assembly, which in turn, through an opening or connector port in the housing, connects to the external electronics. An electrical ground line is one of the electrical connections on the actuator flex cable. This ground line provides a good electrical connection between the read/write chip electrical ground and the disk drive housing. Electrical grounding is increasingly important in disk drive systems to decrease electrical noise affecting the data signal and to minimize electrostatic charge buildup which can result in damage to the read/write transducer.
When considering methods to connect the electronics inside the disk drive housing with the external disk drive electronics, it must be considered that disk drive systems are very sensitive to particulate and chemical contamination which can adversely affect the mechanical reliability. To protect the system from contamination, disk drive housings are generally sealed to isolate the interior of the disk drive from the outside environment. The actuator flex cable connecting the read/write chip and the disk drive electronics is electrically connected to a sealed connector pin assembly which is mounted at the connector port with a suitable gasket seal interface to the disk drive housing. On the inside of the disk drive housing, grounding of the actuator flex cable at the connector port is very important to improve signal-to-noise ratio during use of the drive and to protect the electronics and read/write transducer from electrostatic damage during assembly and handling.
In the prior art, electrical connection of the actuator flex cable ground line to the disk drive housing is made with a variety of mechanical connectors such a screws, springs, pins or other fastening devices. For example, in U.S. Pat. No. 5,541,787 assigned to Jabbari et al., grounding of the actuator flex cable to the disk drive housing by means of screws is described. A second example is the IBM Technical Disclosure Bulletin, Vol. 38, No. 02, February 1995, describing a spring soldered to the actuator flex cable ground which contacts the disk drive housing when the drive is assembled. The disadvantages of the prior art methods for providing actuator flex cable grounding are the need for extra components, the added assembly steps required and the risk of introducing contamination inside the disk drive housing.
It therefore can be seen that there is a need for an apparatus and a method for grounding the actuator flex cable to the disk drive housing which provides a reliable electrical ground contact with no additional parts or assembly steps and no sources of additional particulate contamination.